bug with the upload, we don't see what was the message sent by S;
also this girl is sleep deprived, paranoid and overall in shock of having essentialy witnessed a murder, the poor girl is easily manipulated, she kept shut because she thought that was for the best since she had no proof, and then now she feels she has to keep quiet because it's too late, those texts talking in "we"had her think if she comes clean now, she'll be branded as a partner in crime;
damn ... fear is just soo exploitable;